1. Part 1 The Field of the Invention
This invention relates to solid correction compositions which are applied to a marking to form a film over the marking which can effectively obscure the marking and receive and retain a corrected marking.
2. Part 2. Description of the Prior Art
Solid correction compositions are known and have been proposed as replacements for liquid correction fluid compositions in correcting markings. Solid correction compositions present obvious advantages over liquid correction fluids since there is no need to wait for evaporation of liquid components or any need to use volatile organic fluids in the compositions. Solid correction compositions are disclosed and described in Japanese Patent Applications 61-11610 and 62-33142. Correction compositions disclosed in Japanese Patent application 61-11610 comprise solid dispersions of opacifying pigment (titanium dioxide) in combination with an ester wax, a vinyl chloride copolymer, drying oils (linseed and tung oils) and a plasticizer (vinyl butyl phthalate and water epoxy). Japanese Patent Application 62-33142 discloses correction compositions comprising a solid dispersion of titanium dioxide in combination with a wax and an ethylene-vinyl acetate copolymer.
The performance characteristics of the solid correction compositions of the Japanese Patent Applications have been found to be deficient in certain important aspects. For example, one of the most important performance characteristics assigned a liquid or solid correction composition is the capability of the composition to form a film over a marking to be corrected which can both effectively obscure the marking and provide a dry bonded film which can receive and retain a new marking. In the case of the solid correction composition of Japanese Patent Application 61-11610 the film applied to the marking remains moist because of a relatively slow rate of evaporation of the included drying oil and, the covering power of the film was weak. Also, the evaporation of the drying oil from the solid correction composition ultimately renders the composition unusable. On the other hand, films produced by the solid correction compositions of Japanese Patent Application 62-33142 were found to have poor adhesion and bonding to the paper. Accordingly, there remains an outstanding need in the art for solid correction compositions which can continually and reliably provide a solid film on application to a marking which can both effectively obscure the marking and receive a corrected marking. This invention is addressed to that need and provides an extremely effective response to that need.